Search and rescue personnel is facing many challenges when deployed in the field after a natural or man-made disaster. In some cases they are exposed to safety risks, for instance when searching for trapped victims under a partially collapsed building after an earthquake. Robots could be a tool that the search and rescue teams could use to search in areas that are too dangerous or too difficult to reach. In this paper, part of the effort made by the CURSOR project is described. In particular, we present a software architecture designed and developed for the Soft Miniaturised Underground Robotic Finder (SMURF). The SMURF is a robotic platform designed and built to assist the search and rescue teams during their operations. Finally, we describe the main components of the SMURFs and share our findings and our acquired experience when developing and testing the SMURFs in realistic environments.